I would like to have 3 streams. I hit more than 1 and the second one starts pausing and unpausing, etcWhy don't you enable hardware encoding and use the QuickSync off of your existing CPU's IGP? Probably cheaper that way. Or get a cheapish video card with NVENC to do the transcoding.
But yes, for pure CPU transcoding the 3950x will run circles around a 4790k. How many concurrent streams do you have at a time?
Most of the current CPUs would do better than your current i7-4790K. The i7-4790K had been lingering in "legacy" support status for a few years now: All of the newer iGPU drivers since about 2017 for that CPU had been merely security fixes to a driver that dated all the way back to 2015. And newer plex programs are now requiring a newer iGPU (and thus a newer version of QuickSync) just to even enable hardware encoding at all. Such depreciated support from Intel itself for a CPU that I had used in my main PC for over five years is the biggest reason why I upgraded from that CPU to an AMD Ryzen 7 3800X back in December of 2019.So I currently have a 4790K and transcoding sucks. First time with an AMD, and someone said that they have come a long way.
So would that CPU do well for plex?